Smoking during pregnancy affects the pulmonary health of future grandchildren

If a woman smokes during pregnancy, there is a higher risk that her future grandchildren will have lung problems and asthma. These are the findings of a study carried out by researchers at the University Medical Center Groningen (UMCG) among 37,000 participants. Their results will be published in the scientific journal Thorax. This is the first time that such an effect on lung function has been established.

Smoking during pregnancy increases the risk of asthma in the unborn child. Previous studies published in scientific literature have already reported that this effect of smoking during pregnancy does not only affect the foetus, but also the immature ova of female foetuses. These ova will eventually become the grandchildren of the woman who smoked during pregnancy. That was the focus of this research. The researchers used the LifeLines cohort study to analyse data relating to almost 26,000 adults and over 11,000 children, making this the largest study until now, demonstrating the effect of grandmothers smoking during pregnancy on the health of future grandchildren.

Greater risk of reduced lung function

The research revealed for the first time that smoking during pregnancy increases the risk of reduced lung function in male grandchildren. The reason why this particularly affects boys is not completely understood. It could be hormonal related or due to the fact that male foetuses tend to grow faster in the womb and can therefore be more vulnerable to unfavourable conditions. The research also showed once again that smoking during pregnancy is a risk factor for asthma and for asthma in children younger than the age of six. Another clear result from the study is that the negative effects of smoking cigarettes during pregnancy can be seen in the pulmonary health of consequent generations. In addition, the research showed that these effects are particularly visible in male offspring.

Grandmother on the mother's side

The research revealed that these effects occur if the grandmother on the mother's side smoked while she was pregnant. The effect of the grandmother on the father’s side having smoked during pregnancy was also examined, but this does not appear to have any discernible consequences. This is probably because a woman’s ova develops while she is still in the womb, while male sperm cells do not develop until puberty. In other words, men are not directly exposed to the effects of smoking.

Implications of indirect exposure to smoking for future generations

These effects of smoking are the result of direct exposure, so-called intergenerational inheritance. The researchers now want to conduct a generational study of the consequences of indirect exposure; transgenerational inheritance. Initial research of this phenomenon in animals shows that this effect exists, indicating that the negative consequences of smoking on future generations are far greater than had previously been assumed.